"He would say 'isn't it cool? Did you watch the news?'" Devin Kelley (l.) reportedly told a colleague of the 2015 mass murder by Dylann Roof (r.) in a Charleston church.

The sick shooter behind the Texas church massacre admired another deranged killer — Dylann Roof — and boasted about buying animals for “target practice,” one of his former Air Force supervisors said Thursday.

Jessika Edwards told CNN she served at Holloman Air Force Base in New Mexico with Devin Kelley between 2010 and 2012.

Years before Kelley stormed First Baptist Church in Sutherland Springs last Sunday and killed 26 people, he raised numerous red flags, causing “problem after problem,” Edwards said.

He was reportedly thrilled after Roof opened fire in a historic black church in Charleston, S.C., and murdered nine worshipers in June 2015.

In 2012, Kelley was sentenced to 12 months confinement in the Air Force’s brig for beating his wife and stepson. He shook the toddler so hard he fractured the child’s skull.

Dylann Roof gunned down nine worshippers in his 2015 massacre.

While being investigated by the Air Force for the domestic violence case, Kelley escaped from a mental institution — but not before boasting to other patients that he’d recently gone on an online firearm shopping spree, according to reports.

Kelley was taking medication for depression, anxiety and attention deficit hyperactivity disorder at the time.

After serving his sentence he was kicked out of the Air Force for bad conduct.